RAW related

Windows

iRAW (OS) - This is a free multiplatform software based on dcraw. Convert RAW files generated by CHDK firmware.

DCRaw (OS) - command line RAW converter; DCRaw is the core software for many RAW converters

UFRaw (FREE) - RAW app based on DCRaw, comes along with plug-in functionality for GIMP

Adobe Lens Profile Creator (FREE) - a free utility to create lens profiles for use in the Photoshop® family of products (Photoshop CS5, Camera Raw plug-in & Lightroom®). A lens profile describes the types of optical aberrations that exist in a particular lens and prescribes how to correct the lens distortions in an image captured from the same lens

Stacking & HDR

CombineZM - FREE a great stacking software, also listed in the table above (direct download link)

Picolay - Another FREE focus-bracket stacking program, even easier to use with the same or better results than CombineZM. Also allows the creation of macro photography stereo-pairs by just using the out-of-focus bokeh data from your one-point-of-view focal-plane image stack. No need to shift point-of-view to create stereo-pairs, the out-of-focus data in your images already contains that information for you, it's just a matter of mathematically extracting it.

Photorec - OS a companion program to TestDisk. Photorec is a file data recovery software designed to recover lost files including video, documents and archives from hard disks and CDROM and lost pictures from digital camera memory. PhotoRec ignores the filesystem and goes after the underlying data, so it will still work even if your media's filesystem has been severely damaged or re-formatted.

iBored - FREE a hex editor for disk sectors, but can also be used to edit files, including disk images (Mac, Linux, Windows)

VirtualDub - OS a video capture/processing utility for 32-bit and 64-bit Windows platforms (98/ME/NT4/2000/XP/Vista/7), licensed under the GNU General Public License (GPL)